Comment on ‘ ‘ Solving the mystery of booming sand dunes ’ ’ by Nathalie

[1] We show here that the standard physical model used by Vriend et al. [2007] to analyse seismograph data, namely a non-dispersive bulk propagation, does not apply to the surface layer of sand dunes. According to several experimental, theoretical and field results, the only possible propagation of sound waves in a dry sand bed under gravity is through an infinite, yet discrete, number of dispersive surface modes. Besides, we present a series of evidences, most of which have already been published in the literature, that the frequency of booming avalanches is not controlled by any resonance as argued in this article. In particular, plotting the data provided by Vriend et al. [2007] as a table, it turns out that they do not present any correlation between the booming frequency and their estimate of the resonant frequency.